DANVILLE (CBS SF) — A Contra Costa County sheriff’s deputy who was arrested Friday on drug charges had allegedly been working with a Concord-based private investigator to conduct so-called “dirty DUI” stops on clients’ husbands to damage their reputations, an investigator said in an affidavit.

In one of the cases, the target was cheating on his wife and the deputy was looking to “dirty him up” for a future legal battle, according to the affidavit.

He may also face charges of conspiracy and extortion in connection with the alleged drunken driving stops, prosecutor Harold Jewett said Wednesday.

In an affidavit for a search warrant dated March 4, Contra Costa County sheriff’s Detective Sgt. Jason Vorhauer wrote that a reserve deputy named William Howard had approached him and said he had been on patrol with Tanabe in Danville on Jan. 14 when one of the “dirty DUI” stops was conducted.

Howard told Vorhauer that Tanabe had received eight to 10 phone calls from someone he called his “PI friend,” later identified as Christopher Butler, regarding a man who was allegedly drinking alcohol at a local wine bar called The Vine.

Butler, 49, was arrested Feb. 16 along with 49-year-old Norman Wielsch, the commander of the state-run Central Contra Costa County Narcotic Enforcement Team, or CNET.

Prosecutors have alleged that Wielsch stole drugs from law enforcement evidence lockers and gave them to Butler, who sold them through his private investigator business.

The pair have pleaded not guilty to 28 charges, including conspiracy; selling methamphetamine, marijuana and steroids; and possessing methamphetamine, marijuana and steroids for sale.

During their arraignment last week, prosecutor Jun Fernandez alleged that Butler hired attractive women to lure his targets to local bars and invite them to drink. Butler would then allegedly contact local law enforcement officers and have the men arrested for drunken driving, Fernandez said.

Vorhauer wrote in his affidavit that Howard told him Butler had been parked in a Hummer near the bar on the night of the Jan. 14 “dirty DUI” arrest and had given Tanabe a description of the subject’s vehicle. When the man came out of the bar, Butler alerted Tanabe, according to the account.

Tanabe, who was in a patrol car, followed the man until he made a right turn without signaling and pulled him over, according to the document. After the stop, Tanabe arrested the man on suspicion of drunken driving.

Tanabe later allegedly told Howard that it was all a setup, according to the affidavit.

Investigators later learned that the wife of the man who was targeted had allegedly paid Butler $5,000 to conduct an investigation into her husband’s activities.

A district attorney’s investigator told Vorhauer that a search of Butler’s cell phone confirmed that Butler and Tanabe had made arrangements by text message to have the man arrested, according to the affidavit.

Cell phone records also confirmed that they had arranged by text to have another man arrested on Jan. 9, according to Vorhauer.

A second deputy, identified in the affidavit as Tom Henderson, told Vorhauer of a third DUI arrest he had been involved in with Tanabe.

Henderson said that on March 2, he had received a call from Tanabe, who said he was off duty in a bar in downtown Danville and a man he identified by name was drinking heavily and would be leaving soon, according to the affidavit.

Tanabe allegedly explained to Henderson that the man was cheating on his wife and he and Butler wanted to “’dirty him up’ for a future court case,” the affidavit states.

Henderson waited for the man to leave the bar and then pulled him over for speeding, determined he was drunk and arrested him on suspicion of DUI, according to the affidavit.

“It is my opinion that Deputy Tanabe has abused his police powers and has been acting as an agent of Butler while on duty as an Officer of the City of Danville,” Vorhauer wrote.

Danville is one of several cities in Contra Costa County that contract with the sheriff’s office for police services.

According to the affidavit, Howard also told Vorhauer that on the day Wielsch and Butler were arrested, Tanabe allegedly went to Howard’s house and told him he was worried his house would be searched during the investigation.

Tanabe allegedly asked Howard if he could store an item at his house while the investigation was going on, the affidavit stated.

Howard later turned that item in to investigator, who determined that it was an illegal assault rifle, according to the affidavit.

Jewett, who is overseeing the case while Fernandez is out of town, said that since Tanabe posted $260,000 bail on Saturday, there is no urgent deadline to file charges.

Jewett said he does not expect to file charges against him this week, since the investigation is still under way.

Wielsch and Butler are scheduled to return to court April 21 to set a date for a preliminary hearing.

(Copyright 2011 by CBS San Francisco. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed. Wire services may have contributed to this report.)

Well Amber let me explain. There are two sects of society – cops and non-cops. When a non-cop comes over and becomes a cop, he/she is expected to operate with certain principles, integrity, etc. However, if the cop is not able to handle his/her responsibilities with honor and pride, and is not fit to be a cop, we send him back over to your side. This one will be no exception. Sorry he didn’t work out.l